The present invention refers to wind turbines used to produce electrical energy by harnessing the force of the wind, with provision of an anticipated structural arrangement that improves the features of construction, erection and operation of the wind turbine.
The environmentally-friendly nature that defines wind energy, in addition to the progress that has been achieved in technological terms, leads wind energy to be increasingly used as a drive means for producing electricity, through the use of the so-called wind turbines.
Said wind turbines generally consist of a blade rotor, by means of which the power of the wind is used to effect a rotary action that operates a generator for producing electricity.
In wind turbines currently in use, the blade rotor consists of a core or hub, with respect to which the blades for harnessing the action of the wind are radially mounted; axially attached to said hub there is a shaft upon which the rotor of the generator producing the electricity is mounted, in a manner that said shaft is fitted axially in rotary assembly with respect to the body of the wind turbine, in which the stator of the electric generator is mounted in a fixed position, whilst the rotary arrangement of the shaft is established by means of a coupling using bearings.
This structural design of the wind turbines implies considerable difficulties in the erection, given the components of the installation and the couplings that have to be effected between them, rendering them susceptible to noise, vibration and resonance during operation.
The blades harnessing the action of the wind rotate on the hub, in order to yaw the positioning of the same in response to the power of the wind, using for this electric drive motors associated with the individual blades; this requires an expensive assembly and, furthermore, a possible electrical power supply failure renders inoperable the yaw rotation of the blades, making it necessary to provide emergency batteries or accumulators, given that said rotary drive for the yaw of the blades must always be operational to avoid deterioration in the event of strong gusts of wind and to exert a suitable control that will permit achieving the best performance from the wind turbine at each moment.
In accordance with the invention, a wind turbine is proposed that is fitted with a number of improvements that permit is significantly enhanced design with regard to those features described above.
The wind turbine covered by this invention consists of a blade rotor that comprises a hub that is prolonged at the rear with an extension that constitutes the shaft upon which the rotor of the electric generator is mounted, in a manner whereby the shaft and the hub structurally conform a single piece, to which the blades for harnessing the action of the wind are attached, in addition to the assembly of the rotary coupling with regard to the body of the wind turbine.
The single piece of the shaft-hub is closed at the rear by means of a cover that is fitted as an integral part of the same, upon which and axially attached to the outer part there is a boss, with respect to which the manifold of the electric generator is mounted, in addition to a coupling bearing on a mount attached to the casing of the body of the wind turbine; a bearing which is coupled directly to the casing of the body of the wind turbine is attached on the forward area of the part of the single piece that constitutes the shaft.
This thus provides a simple construction structure, as the hub unit of the blade rotor and the shaft of the rotary assembly only require the manufacture of a single piece, which is contemplated in boiler steel, with no need to perform any kind of coupling assembly between said parts; furthermore, the single piece unit of this assembly facilitates the erection of the wind turbine.
It is contemplated that the assembly will be performed by means of elastomeric runners between the part that constitutes the shaft and the casing of the body of the wind turbine, whereby a rotary assembly is achieved that absorbs vibrations and avoids resonance.
With regard to the assembly of the blades for harnessing the action of the wind, which are fitted for rotation on the hub, hydraulic drive-cylinders are provided, by means of which each blade can be rotated individually, in order to adjust the positioning of the same in response to the power of the wind.
This means a very straightforward installation, given that no motors are used, nor the corresponding necessary transmission, for said yaw function of the blades of the wind turbine; rather, said function is addressed using hydraulic cylinders, which are much easier to assemble and furthermore permit greater accuracy in the yaw movement of the blades, as no coupling transmissions are required.
In addition, this arrangement of hydraulic cylinders removes the need for providing emergency electrical accumulators to cater for the possibility of failure in the electrical power supply, with only hydraulic accumulators required, which are of much lower cost and more reliable.
It is necessary to provide a small battery for operating the servovalve for each cylinder; but this battery is very small, simple and of minimal cost compared to the electrical accumulators required for feeding the electric motors that operate the blades in traditional designs, in the event of a failure in the power supply.
In view of all the above, the aforementioned wind turbine covered by the invention certainly provides highly advantageous characteristics, standing apart with distinct features with regard to those wind turbines that are currently known.